There was no immediate answer for what might have caused the chunks to come loose along a 60-foot stretch of the back of the Science Building's façade facing the athletic field on Bamford Avenue on Sept. 12.
No work was being done at the time, responders said.
The collapsed section of parapet wall pulled a swatch of the frieze down with it.
Two sedans and a van were damaged.
School officials were joined by police and firefighters.
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